1. Field of the Invention
The present invention relates to a coating from which deposits are easily removed with water and the like, and a method for using the same. In particular, the present invention relates to a coating which is formed on the surface of a material and makes it possible to repeatedly remove deposits from the surface (hereinafter referred to as a "deposit-easy-removable coating").
The coating of the present invention does not prevent the adhesion of deposits by nature. Rather, it allows the adhesion of the deposits and easy removal of the deposits by the treatment with water and the like. Thus, such a coating is herein referred to as a "deposit-easy-removable coating".
2. Description of Related Art
It is difficult to remove deposits from material surfaces. Even oils should be cleaned with a quantity of water containing a surfactant with considerable labor, or with organic solvents which are harmful to the human body or environment.
Since waxy or solid deposits are hardly removed with the surfactants, they should be removed with organic solvents, or mechanically scraped off, which require heavy work. But, such deposits may not be completely removed, or the materials to which the deposits adhere may be damaged. In many cases, the waxy or solid deposits are not removed.
It is possible to remove the deposits by forming a releasable or soluble coating on material surfaces and removing the deposits together with the coating. However, whenever the coating is removed, a fresh coating should be formed, or the removed coating generates an additional waste. Therefore, this technique does not provide an essential solution.
As coatings from which the deposits can be repeatedly removed, coatings of fluororesins (for example, TEFLON.TM.) are known. However, they are not widely used, since they are expensive, kinds of surfaces on which such coatings can be formed are limited, they have low transparency, or materials are hardly used with carrying deposits such as characters because of too easy removal of the deposit.
In the case of office automation sheets such as OHP (overhead projector) films or papers for copying, and the like, they are used and wasted in a large scale and cause the environmental problem, since inks cannot be removed from their surfaces.
As a measure for solving the above problems, EP-A-0 601 502 discloses fixing, to a surface of a material, of a deposit-easy-removable coating which consists of a film comprising a hydrophilic resin that is in a solid state at room temperature in an air, and which swells but is not washed off with water.
Deposits can be easily removed from the deposit-easy-removable coating disclosed in the above EP application by cleaning with water without causing adverse effects on the human body or environment. However, the removal of deposits, which have a high adhesion force or have high viscosity and thus easily redeposit on the surfaces, requires a long time, and the removing procedures should be repeated to remove such deposits sufficiently. Thus, deposit-removing properties of the coatings should be further improved from the practical point of view.